Gas filled discharge tube



G. HOLST GAS EFILLED DISCHARGE TUBE April 25, 1933.

' Filed Jan. 22, 1927 Patented Apr. 25, 1933 PATEN'EE.

Fries GILLES HOLST, OF EINDHOVEN, NETHERLANDS, ASSIGNOB, BY MESNE ASSIGNMENTS,

TO GENERAL-ELECTRIC COMPANY, A CORPORATION OF NEW YORK GAS FILLED mscrmnen TUBE Application filed January 22, 1927, Serial No. 162,900, and-in the Netherlands January 29, 1926.

With enclosed arc discharges the heating of the anode is dependent on the nature of the gaseous filling, for if the latter consists of a non-rare gas such as nitrogen, the heating of the anode is equal to the product of the current intensity and a voltage '0 which in the case of tungsten anodes is about 20 volts, whereas with arc discharges in a rare gas this voltage v only amounts to about 4 volts. It is evident that the latter case is more unfavourable than the former as in order to obtain the same heating effect a much greater current intensity is needed so that on that account the use of a-filling of nitrogen would be preferable. On the other hand, however, a gaseous filling consisting of one of the rare gases presents the advantage that the arc can be struck more easily. The invention has for its object to combine the two advantages by taking such measures that in the case of arc discharges in a rare gas the said voltage '0 can be raised to a value considerably higher than 4 volts.

According to the invention, this purpose is attained by arranging between the main electrodes one or more fixed auxiliary electrodes which are shaped so as to allow the discharge to pass, but which take a negative potential 7 during this discharge.

In that case the auxiliary electrode may consist of an insulatedly arranged ring or of a ring which, being provided with a leading-in wire of its own, may be connected to the negative pole of the source of current.

The accompanying drawing represents diagrammaticall two embodiments of the invention in WhlCl'l only those parts of the arc lamp are indicated by reference numerals which directly have relation to the invention.-

In the drawing:

Figure 1 illustrates the case where the auxiliary electrode is arranged so as to be insulated and Figure 2 represents the case in which the auxiliary electrode is provided with a leadingin wire of its own.

Between two spherical electrodes 1 and 2 which for example may be made of tungsten, is arranged an'annular auxiliary electrode 3 of such diameter that it does not impede the discharge between the electrodes land 2.

The main electrodes 1 and 2 as well as the auxiliary electrode 3 are sealed into the pinch of a glass foot 4. Inthe case illustrated in Figure 1 only the electrodes 1 and 2 are provided with leading-in wires. Whenever a discharge between the electrodes 1 and 2 is produced, no matter whether it is a direct current or an alternatin current discharge, a negative potential wi be impressed on the ring 3 under the influence of the negative elec trons produced in great numbers. Due to this negative potential the ring 3 exerts an attractive action on all positive ions that try to diffuse! towards the anode. As, probably, 65 1t is just these positive ions which in the case i of an arc discharge in a rare gas reduce the said voltage 'v by partly neutralizing the negative space charge around the electrode which momentarily or continuously acts as an anode, this voltage will be considerably in-' creased owing to the presence of the ring 3. In accordance therewith it has been found that in neon thisv voltage can be raised to about 25 volts-instead of to 4 volts only, when used without the auxiliary electrode 3.

It will be evident that it is not absolutely necessary that the auxiliary electrode 3 should have an annular shape, but also other shapes for example that of a frame may be used. It is essential that the auxiliary electrode should allow the arc discharge to pass unhindered without itself taking part'in it and that during this discharge.it should attract the diffusing positive ions} K It will also be clear that it is not necessary to arrange the rin 3 between the electrodes 1 and 2 so as to e insulated but that this ring may be provided with a leadingout wire of its own, said wire being connected in that case to a point having a negative potential, for example, to the negative pole of the source of current. An example thereof is illustrated in Figure 2 in which the negative pole is connected directly to the ring 3 and through a steadying resistance 5 to the cathode 2 of the discharge tube. It is obvious that this case can only be considered 1. An electric arc discharge tube comprising a rare gas-filling, main cooperating electrodes and a ring-shaped auxiliary electrode for increasing the arc voltage, said ringshaped electrode being mounted entirely between said main electrodes and surrounding the discharge path.

2. An electric discharge tube comprising a rare gas-filling, main cooperating electrodes and an auxiliary electrode for increasing the arc voltage, said auxiliary electrode being mounted entirely between said main electrodes and provided with a leading-in wire.

3. An electric device comprising a source of current and an arc discharge tube, containing a "rare gas-filling, a main anode, a mairf cathode, and a fixed auxiliary electrode for increasing the arc voltage mounted entirely between said main electrodes and surrounding the arc dischargepath, and provided with a leading-in wire, said leading-in wire being connected to the negative pole of said source of current, and an ohmic resistance connected between said negative pole and said main cathode.

4. An electric arc discharge tube comprising a rare gas-filling, main cooperating substantially spherical electrodes and a fixed said electrodes for the purpose of segregating positive ions from said discharge path.

In testimony whereof I aflix my signature, at the city of Eindhoven, this 28th day of December, 1926.

substantially annular auxiliary electrode for increasing the are voltage, said auxiliary electrode being mounted entirely between said main electrodes and surrounding the are discharge path .and adapted to assume during the discharge a negative potential with re- I spect to the electrode acting as an anode.

5. An electric arc discharge tube comprising a filling of neon, main cooperating substantially spherical tungsten electrodes and 4 a fixed substantially annular auxiliary elec- Q trode for increasing the arc voltage, said auxiliary electrode being mounted entirely between said main electrodes and surrounding the arc discharge path and adapted to assume during the discharge a; negative potential with respect to the electrode acting as an anode.

6. An electric arc discharge tube comprising a sealed envelope, a rare gas filling and main discharge electrodes in said envelope, in combination with an auxiliary electrode w mounted entirely between said main electrodes and circumscribing the discharge path 7 between said main electrodes while permitting a free discharge to be established under A ahigher voltage than exists as a direct discharge between said electrodes in the absence of the auxiliary electrode.

7. An electric arc discharge tube comprisv GILLES HOLST. 

